Cold in-place recycling of bituminous material statement regarding federally sponsored research or development

ABSTRACT

A method of reconstructing a road is provided. This method includes taking representative cores of the road, analyzing the cores, selecting a substantially solvent-free emulsion based on climate history, mixing the emulsion and reclaimed asphalt pavement particles to form an asphalt emulsion mix, testing the asphalt emulsion mix for performance using a raveling test, a thermal cracking prediction test by an indirect tensile testing, a moisture susceptibility test utilizing vacuum saturation, and a dry Marshall stability test. It also includes designing a CIR layer based on this test data. It further includes grinding off a layer of the existing asphalt road leaving at least about an inch, adding an emulsion to the reclaimed asphalt pavement particles, applying the designed cold in-place recycling layer to the road, and compacting it.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0001] Not Applicable.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] Not Applicable.

BACKGROUND OF THE INVENTION

[0003] The present invention relates to reconstructing and paving roads.More specifically, the present invention is a cold in-place recycling(CIR) method for designing an asphalt emulsion mix and building a road.

[0004] Traditionally, when roads are rehabilitated, material is milledand removed. Then, hot mix is brought to the construction site andplaced on the milled area. One disadvantage with such a process is thatit is time consuming because it requires two operations. In oneoperation, the road is milled up, and the material is removed. Then, inthe second operation, the hot mix asphalt is transported to the site andplaced on the milled pavement. Another disadvantage with such a processis that the milled material is often not reused.

[0005] More recently, roads that are in fair or poor condition have beenreplaced or rehabilitated using cold in-place recycling (CIR) of thebituminous material that makes up the road. However, these CIR processeslack thorough designs and thus have consistency problems, such asinconsistency in emulsion content. Many times they do not provide thedesired performance. Still further, roads made with conventional CIRprocesses are unreliable, and many times this leads to raveling, potholes, rutting, disintegration problems, and cracks.

[0006] In order to overcome these disadvantages, a process that providesbetter road performance while using recycled materials is needed.

SUMMARY OF THE INVENTION

[0007] It is an object of the present invention to provide a coldin-place recycling method that has improved performance and moreconsistency so that severely distressed pavement can be rehabilitated.

[0008] According to the present invention, the foregoing and otherobjects are achieved by a method of reconstructing a road. This methodincludes taking representative cores of the road, analyzing the cores,crushing the cores, selecting a solvent-free emulsion based on climatehistory, mixing the emulsion and reclaimed asphalt pavement particles(RAP) to form an asphalt emulsion mix, and testing the asphalt emulsionmix for performance using a raveling test, a thermal cracking predictiontest by indirect tensile testing, a moisture susceptibility testincorporating vacuum saturation, and a dry Marshall stability test. Italso includes designing a CIR layer based on this test data. It furtherincludes grinding off a layer of the existing asphalt leaving at leastabout an inch of pavement, adding an emulsion to the reclaimed asphaltpavement particles, applying the designed cold in-place recycled layerto the road, and compacting it.

[0009] Additional objects, advantages, and novel features of theinvention will be set forth in the description that follows and in partwill become apparent to those skilled in the art upon examination of thefollowing, or may be learned by practice of the invention.

BRIEF DESCRIPTION OF THE FIGURES

[0010] In the accompanying figures, which form a part of thespecification and are to be read in conjunction therewith:

[0011]FIG. 1 is a graph showing sieve analysis of the RAP and rock usedin the CIR process of the present invention as it was performed inExample 1;

[0012]FIG. 2 is a graph showing retained strength data from the moisturesensitivity vacuum saturation test performed in Example 1 in accordancewith the present invention;

[0013]FIG. 3 is a graph comparing Asphalt Pavement Analyzer data at 50°C. for a specimen made in accordance with the present invention and aconventional specimen as discussed in Example 1;

[0014]FIG. 4 is a is a graph showing sieve analysis of the RAP and rockused in the CIR process of the present invention as it was performed inExample 2;

[0015]FIG. 5 is a graph showing the results of the raveling testperformed in Example 2 in accordance with the present invention;

[0016]FIG. 6 is a graph showing sieve analysis of the RAP used in theCIR process of the present invention as it was performed in Example 3;

[0017]FIG. 7 is a graph showing stiffness measurements at variousstations on the road as measured in Example 3 in accordance with thepresent invention;

[0018]FIG. 8 is a graph showing sieve analysis of the RAP and rock usedin the CIR process of the present invention as it was performed inExample 4;

[0019]FIG. 9 is a graph comparing the Resilient Modulus at 25° C. of aspecimen made in accordance with the present invention and aconventional specimen as discussed in Example 4; and

[0020]FIG. 10 is a graph showing indirect tensile strength of specimensmade in accordance with the present invention in Example 4 with 3% byweight emulsion.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0021] The cold in-place recycling process of the present invention canbe considered when a pavement surface is at the end of its serviceablelife. When pavement exhibits alligator (fatigue) cracking, thermalcracks, raveling and potholes, ruts, flushing or bleeding, low skidresistance, or a rough texture, the CIR process of the present inventionmay be desirable. It may be especially desirable where there are lowclearances on bridges and overpasses or where curb heights are aconcern. It may be used on rural roads, intrastate highways andinterstate highways. It is especially useful on distressed pavement thatis about 12-25 years old. The particular design of the CIR materialshould be based on the process and conditions outlined below, which arepart of the present invention. The present invention addresses problemsthat occur with conventional CIR processes such as raveling, thermalcracking, slow curing times, and unreliable performance. The CIR methodof the present invention provides partial depth rehabilitation ofseverely distressed pavement that has a structurally sound base and gooddrainage.

[0022] First, the road is evaluated to see if it is fit for the processof the present invention. The aged pavement must be thick enough toleave at least about an inch of pavement after preferably two to fiveinches of it is milled. Also, the road must have a structurally soundbase, including a structurally sound subgrade layer. Sample cores aretaken to determine variations in pavement, the desired gradation of thereclaimed asphalt pavement particles (RAP) and emulsion amount so as tocreate a mix design. The emulsion formulation is selected based onclimate history and application temperature. The top portion of the agedpavement is ground off as recommended by the mix design leaving at leastabout an inch of pavement. Only the pavement is removed. No rock, gravelor dirt beneath the pavement is removed. The RAP is then combined withthe selected emulsion to form the CIR material of the invented method.This CIR material is then placed on the road and compacted.

[0023] After the road is evaluated, the CIR process of the presentinvention involves making a preconstruction mix design using materialsobtained directly from the project site. Representative cores areobtained from the areas of pavement to be recycled to evaluate theexisting pavement. Preferably, the cores taken are distributedthroughout the project length, including where visual differences in thepavement are noticed. Cores shall be pulverized, crushed, and screenedin the laboratory to form RAP. The RAP is considered black rock oraggregate for purposes of further mix design. If the cores showsignificant differences in various areas, such as different types orthickness of layers, then separate mix designs shall be performed foreach of these pavement segments. The recycled asphalt pavement millingsshall be blended to the following gradation criteria for fine, mediumand coarse mix designs prior to the addition of asphalt emulsion. TABLE1 Sieve size Fine Medium Coarse inches % passing thru % passing thru %passing thru  1.25″ 100 100 100  0.187″ (No. 4) 55-65 40-50 28-380.0234″ (No. 30) 20-25  7-12  4-10 0.0029″ (No. 200) >1.0 >0.5 >0.1

[0024] The mix design shall be performed using these crushed millings.Mix design includes defining gradation and selecting the amount andcomposition of the emulsion. Gradation of the millings after crushingshall be determined by washing the millings and putting them throughvarious sieves. Particle size distribution of the fine and coarseaggregates shall be determined by sieving through a series of sieves ofprogressively smaller openings. Preferably, the Standard Test Methodsfor Materials Finer Than 75 μm (No. 200) Sieve in Mineral Aggregates byWashing (ASTM C117) and Sieve Analysis of Fine and Coarse Aggregates(dried at no greater than 40° C.) (ASTM C136), are followed.

[0025] Samples shall be prepared with a sample splitter to maintainuniformity of material. An alternative method is to dry, screen andrecombine millings in the laboratory to achieve a targeted gradation.Suggested sieves are ½ inch, ⅜ inch, No. 4 (0.187 inch), No. 8 (0.093inch), and No. 30 (0.0234 inch). Oversized RAP particles are removedwith a 1 inch screen when using 100 mm diameter compaction molds.

[0026] Next, the theoretical maximum specific gravity and density of theRAP samples are determined from mass and volume measurements.Preferably, the Standard Test Method for Theoretical Maximum SpecificGravity and Density of Bituminous Paving Mixtures (ASTM D2041) is usedto determine the size for the Rice specific gravity test. Four specimensper emulsion content are desired to test for long term stability andmoisture testing. Two specimens are required for the Rice specificgravity test. The RAP samples are tested for theoretical maximumspecific gravity at the highest emulsion content in the design and thenback calculated for the lower emulsion contents.

[0027] An asphalt emulsion will then be incorporated into the pulverizedmaterial. The type or formulation of asphalt emulsion used shall bedetermined by the climate in which the emulsion is used and thetemperature when it is placed. It may be chosen, for example, to improvecoating of the RAP or to adjust breaking properties. Preferably, themixture cold temperature cracking specification shall be chosen usingdata from FHWA LTPP Bind™ software (Version 2.1) by inputting data fromthe weather station closest to the project. The required temperature forthe mix design specification is the coldest temperature at the top ofthe CIR layer in the pavement structure, using 98% reliability.

[0028] The asphalt emulsion is a blend of asphalt, water, emulsifier,and possibly additives. It is liquid at ambient temperature. Thespecific formulation of the emulsion can vary depending upon theproperties to be achieved. For instance, it can be formulated to set upquickly. It also can be formulated to improve the coating of thebituminous material, to result in less cracking of the roadway or toimprove the strength of the roadway. The type of asphalt emulsion usedshall be determined by the mixture design, discussed infra.

[0029] Preferably, the emulsion includes about 0.5 to 10% by weightemulsifier, about 60 to 65% by weight asphalt solids, water, andoptionally certain additives. Preferably, the emulsion is substantiallysolventless and water-based. The additives may be about 0.5 to 10% byweight of the emulsion and may include elastomers, plastomers, otheradhesion agents, and petroleum fractions. Preferably, it includes amaximum of about 0.5% by weight fuel oil. Depending on which additivesare used, these additives can be added to the asphalt solids or to theemulsion to make modified asphalts, including polymer modified asphalt.The emulsifier can be anionic, nonionic, amphoteric, or cationic. Mostpreferably, the emulsifier is cationic.

[0030] The asphalt emulsion shall be at a temperature no greater thanabout 120° F. during application. Usually, it is between about 80° and120° F. during application. The emulsion quality assurance testing shallmeet the following requirements: TABLE 2 Test Minimum Maximum Residuefrom distillation, % by ASTM D244¹ 64.0 66.0  weight Oil distillate bydistillation, % ASTM D244¹ 0.5 by weight Sieve Test, % by weight ASTMD244¹ 0.1 Penetration (TBD²), ASTM D5 −25% ‘+25% 25° C., dmm

[0031] The emulsion is added to the reclaimed asphalt pavement particles(RAP). The emulsion should be present in a sufficient quantity that themixture is not too dry so as to cause raveling but not in such a highquantity that the mixture easily ruts. The emulsion is usually about 1.5to 4.5% by weight of the mixture. Preferably, it is about 2.4 to 4.0% byweight of the mixture. Most preferably, it is 2.8 to 3.3% by weight ofthe mixture. The recommended emulsion contents for design mixformulations are about 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, and 4.5% byweight emulsion. Preferably, three emulsion contents are chosen thatbracket the estimated recommended emulsion content. Prior to theaddition of emulsion, the amount of moisture that is expected to beadded by the milling head, typically about 1.5 to 2.5% by weight, isadded. If any additives are in the mixture, these additives areintroduced in a similar manner to how they will be added during fieldproduction.

[0032] The reclaimed asphalt pavement particles (RAP) from milling arefirst thoroughly mixed with water, and then they are mixed with theemulsion. Mixing shall occur at approximately ambient temperature. Themixing time with the emulsion should not exceed about 60 seconds.

[0033] The specimens are compacted within about 15 minutes of beingmixed. Preferably, the specimens shall be compacted immediately aftermixing. Paper disks are placed on the top and bottom of each specimenbefore compaction. Preferably, specimens shall be compacted with aSuperpave™ gyratory compactor (SGC) in a 100 mm mold at 1.25° angle, 600kPa ram pressure, and 30 gyrations. The mold shall not be heated.

[0034] The specimens are then extruded from the molds immediately aftercompaction, and the paper disks are carefully removed. The specimens areplaced in a 60° C. forced draft oven with ventilation on its sides andtop, typically for 48 hours. Each specimen is placed in a smallcontainer to account for material loss from the specimens.

[0035] Four performance tests are conducted on these specimens. They area dry Marshall stability test, a moisture susceptibility test usingvacuum saturation, a raveling test, and a thermal cracking predictiontest by indirect tensile testing (IDT). These tests determine theperformance of the specimens. The indirect tensile test predicts thermalcracking, and the dry Marshall stability test measures strength. Theraveling test measures raveling resistance, and the moisturesusceptibility test measures the specimens' ability to withstandmoisture damage. In order for the formulated mix design to be used, itmust meet the criteria set forth below in Table 3 for all of thesetests. TABLE 3 100 mm specimens shall be prepared in a Superpave ™Gyratory compactor. The mixture should meet the following criteria atthe selected design asphalt emulsion content: Property Criteria PurposeCompaction effort, Superpave ™ Gyratory 1.25° angle, 600 kPa DensityIndicator Compactor stress, 30 gyrations Density, ASTM D 2726 orequivalent Report Compaction Indicator Gradation for Design Millings,ASTM C117 Report Marshall stability*, ASTM D 1559-89 Part 5, 1,500 lbmin. Stability Indicator 40° C. Retained stability based on curedstability** 70% min. Ability to withstand moisture damage IndirectTensile Test, AASHTO TP9-96, LTPPBind ™ Cracking (Thermal) Modified asdiscussed infra temperature for climate and depth Raveling Test, MethodAttached, Ambient  2% max. Raveling Resistance temperature

[0036] For the Marshall stability test, specimens are dried to constantweight. Compacted specimens are cured to constant weight but for no morethan 48 hours and no less than about 16 hours. Constant weight isdefined as about 0.05% or less change in weight in 2 hours. Aftercuring, specimens are cooled at ambient temperature a minimum of about12 hours and a maximum of about 24 hours.

[0037] The bulk specific gravity (density) of each compacted (cured andcooled) specimen is determined. The mass of the specimen in water isrecorded after one minute submersion. Specimen heights are alsodetermined.

[0038] The Rice (maximum theoretical) specific gravity is determined.Preferably, it is determined following the Standard Test Method forTheoretical Maximum Specific Gravity and Density of Bituminous PavingMixtures (ASTM D2041) including the dry-back procedure. The agglomeratesthat will not easily reduce with a flexible spatula should not bebroken. It is normally necessary to perform a supplemental dry-backprocedure to adjust for uncoated particles. The amount of air voids aredetermined for each specimen having a different emulsion content.

[0039] Corrected Marshall stability is determined by measuring thepaving mixture's resistance to plastic flow. Preferably, it isdetermined using the Standard Test Method for Resistance to Plastic Flowof Bituminous Mixtures Using Marshall Apparatus (ASTM D1559-89) at about40° C. after 2 hour temperature conditioning in a forced draft oven.

[0040] The moisture susceptibility vacuum saturation test measuresretained strength in the presence of moisture. For the moisturesusceptibility test, the same conditioning and volumetric measurementsare performed on moisture-conditioned specimens as performed on thespecimens used for the dry Marshall stability test. These specimens arevacuum saturated to about 55 to 75% of the volume of voids followed bysoaking them in an about 25° C. water bath for about 23 hours, followedby about a one hour soak at about 40° C. The corrected Marshallstability is then determined. The average moisture conditioned specimenstrength divided by the average dry specimen strength is referred to asretained stability. This is an indicator of stripping and strength loss,which leads to rutting and the formation of potholes. The retainedstability must be greater or equal to about 70%.

[0041] After the dry Marshall stability test and the moisturesusceptibility test are performed, an indirect tensile test (IDT) isperformed on the mixture at the designed emulsion quantity. This IDTperformance test estimates the cold temperature cracking initiation ofthe mixture. It predicts the coldest temperature that the mixture canwithstand and avoid cracking at the top of the CIR layer. Preferably,the indirect tensile test is performed according to AASHTO TP9-96, whichis the Standard Test Method for Determining the Creep Compliance andStrength of Hot Mix Asphalt (HMA) Using the Indirect Tensile TestDevice, with the following exceptions:

[0042] Specimens shall be about 150 mm in diameter and at least about115 mm in height and compacted to air voids±1% of the designed air voidsat the designed emulsion content. Test specimens shall be cured at 60°C. for no less than about 48 hours and no more than about 72 hours. Thespecimen mass should be checked every 2 hours after the 48-hour cure todetermine if there has been no more than about a 0.05% change in mass in2 hours. After curing, two specimens shall be cut from each compactedspecimen to about 50 mm in height. A bulk specific gravity test is thenperformed after cutting.

[0043] Preferably, two specimens are the minimum required at each ofthree temperatures. Three temperatures at about 10° C. intervals thatbracket the required specification temperatures are selected. Forexample, if the required specification temperature is −25° C., thentesting temperatures of −20° C. and −30° C., and −10° C. or −40° C.should be selected. The tensile strength test shall be carried on eachspecimen directly after the tensile creep test at the same temperatureas the creep test. The environmental chamber must be capable of reachingtemperatures at least as low as about −40° C.

[0044] The critical cracking temperature is defined as the plottedintersection of the calculated pavement thermal stress curve (derivedfrom the creep data) and the tensile strength line (the line connectingthe results of the average tensile strength at the three temperatures).To pass this test, the predicted thermal cracking temperature by IDTshould meet the requirements defined by the LTPP Bind™ program, at 98%reliability, for the coldest temperature at the top of the CIR layer inthe climate in which the project is performed.

[0045] After the Marshall stability and moisture susceptibility testsare performed, a raveling test is also performed on the specimens at thedesigned emulsion quantity. The raveling test is an indicator ofraveling that may occur before the material is fully cured due totraffic driving on the material. Four hours after the sample iscompacted, it is tested for about 15 minutes. To pass this test, theremust be a mass loss of less than about 2% by weight.

[0046] Preferably, the apparatus used for conducting the raveling testis an A-120 Hobart mixer that is modified to allow the sample and anabrasion head (including hose) to fit properly for abrasion. Preferably,the Test Method for Wet Track Abrasion of Slurry Surfaces (ISSA TB-100)is followed for conducting the raveling test, and the rotation speed forthe raveling test is not modified. The ring weight is removed from theabrasion head for the raveling test. The weight of the abrasion head andhose in contact with the specimen should be about 600±15 g. The preparedsample must be able to be secured under the abrasion head and centeredfor accurate results, allowing for free vertical movement of theabrasion head. The device used for securing and centering the samplemust allow a minimum of about 1 cm of the sample to be available forabrasion.

[0047] The raveling test is conducted as follows. Two recycled asphaltsamples from the medium gradation or the field sample of a quantity ofabout 2700 g are split out from the specimens. The 2700 g is anapproximate weight to give 70±5 mm of height after compaction. Therecycled asphalt sample (2700 g) should be placed in a container ofadequate size for mixing. Field or design moisture contents should beadded to each of the recycled asphalt samples and mixed for about 60seconds. The designed emulsion content shall be added to each of therecycled asphalt samples and mixed for about 60 seconds. The samplesshall be placed immediately into a 150 mm gyratory compaction mold andcompacted to 20 gyrations. If the sample height is not 70±5 mm, therecycled asphalt weight should be adjusted. After compaction, thesamples shall be removed from the compaction mold and placed on a flatpan to cure at ambient lab temperature (about 65-75° F.) for about 4hours ±5 minutes. The specimens shall be weighed after the curing, justprior to testing.

[0048] The specimens shall be placed on the raveling test apparatus.Care should be taken that the specimen is centered and well supported.The area of the hose in contact with the specimen should not have beenpreviously used. It is allowable to rotate the hose to an unworn sectionfor testing. The abrasion head (with hose) shall be free to float overthe sample and move vertically downward a minimum of about 5 mm ifabrasion allows. The samples shall be abraded for about 15 minutes andimmediately weighed.

[0049] The percent raveling loss shall be determined as follows: ((Wt.Prior to test—Wt. After abrasion)/Wt. Prior to test)*100. The average ofthe two specimens shall be reported as the percent raveling loss. Thereshould not be a difference of greater than about 0.5% raveling lossbetween the two test specimens for proper precision. A difference ofgreater than about 0.5% will require the test to be repeated. If both ofthe samples have a raveling loss of greater than about 10% the numbersshall be averaged, and the precision rule will be waived.

[0050] If necessary, additives may be used to modify the mix design tomeet the requirements in Table 3. Additives, such as lime, additionalaggregate, polymers, or combinations thereof may be added to the mix tomeet Table 3 requirements. If available, additional crushed RAP materialmay be added if it meets the requirements in Table 4. The crushed RAPshall be substantially free from vegetation and all other deleteriousmaterials, including silt and clay balls. The crushed RAP shall notexceed the maximum size requirement discussed above, and when blendedwith the design millings it shall produce a product that meets thespecifications given in Table 3. TABLE 4 Additional Crushed RAP TestsMethod Limit Deleterious Materials: Clay ASTM C 142 or 0.2 recommendedLumps and Friable Particles in AASHTO T112 Aggregate, % max Maximumsize, 100% Passing, ASTM C 136 or 1.25 inch Sieve Size AASHTO T27

[0051] If additional aggregate is required, it shall meet therequirements in Table 5, and it shall be graded to produce a productwhich meets the specifications given in Table 3. TABLE 5 AdditionalAggregate Tests Method Limit Los Angeles abrasion value, AASHTO T 96 40max for Surface mix % loss 50 max for Base mix Sand Equivalent, % ASTMD-2419 60 minimum Maximum size, 100% ASTM C 136 1.25 inch Passing, SieveSize or AASHTO T27 Water absorption % AASHTO T85  5 max.

[0052] If the pavement significantly varies at different places in theroad, then one should attempt to develop mix designs that meet thecriteria of Table 3 for each of the differing segments of road. Forinstance, some areas of the road may require higher emulsion contentsthan others.

[0053] Before placing the CIR material on the road, grass and othervegetation shall be removed from the edge of the existing pavement toprevent contamination of the pulverized bituminous material during themilling operation.

[0054] The pavement surface temperature may be as high as about 160° F.during construction without creating any problems. The existing pavementshall be milled to the desired depth and width leaving at least aboutone inch of pavement on the road and not removing any gravel, dirt orstone. Usually, between about 2 and 5 inches of pavement are removedwhen the road is milled. Samples of pulverized bituminous material shallbe obtained about each ½ mile before emulsion addition and screenedusing a 1.25 in. sieve (or smaller sieve if required) to determine ifthe pulverized material meets the maximum particle size requirement ofthe design mix. A sample or samples taken at the beginning of theproject will determine which design gradation the pulverized material isclosest to in order to define emulsion content.

[0055] A self-propelled cold milling machine is used to pulverize theexisting bituminous material in a single pass to the desired depth, andpreferably, it is capable of milling to a width of up to about 12.5feet. Preferably, the machine shall have automatic depth controls tomaintain the cutting depth to within ±¼ in. of the desired depth andshall have a positive means for controlling cross slope elevations.

[0056] A material sizing unit having screening and crushing capabilitiesis used to reduce the pulverized bituminous material to the desired sizeprior to mixing it with asphalt emulsion. Preferably, the screening andcrushing unit shall have a closed circuit system capable of continuouslyreturning oversized material to the crusher. All of the reclaimedasphalt pavement shall be processed to meet the maximum sizerequirements.

[0057] A mixing unit equipped with a belt scale for the continuousweighing of the pulverized and sized bituminous material is used.Preferably, it is coupled with a computer controlled liquid meteringdevice. Preferably, the mixing unit shall be an on-board completelyself-contained pugmill. Preferably, the liquid metering device shall becapable of automatically adjusting the flow of asphalt emulsion tocompensate for any variation in the weight of pulverized material cominginto the mixer. Preferably, there is two-way communication between thepaver and the pugmill unit to keep them near to one another. Preferably,they are within about 50 yards of each other.

[0058] The asphalt emulsion and water shall be incorporated into thepulverized bituminous material at the initial rate determined by the mixdesign(s). The total water content may include the amount added at themilling head and may also include additional water from the mixing unit,if available. Adjustments in the rate of asphalt emulsion and water aremade as necessary based on the coating and breaking properties. The RAPshould be more fully coated than conventional processes. Sampling andmix design may determine that different levels of asphalt emulsion areneeded at various portions of the road.

[0059] The CIR mixture exits the pugmill and is laid on the road to forma windrow. A pick-up machine may be pushed by the paver and used fortransferring the recycled material from the windrow to the receivinghopper of the bituminous paver. The pick-up machine shall be capable ofremoving the entire windrow down to the remaining underlying material.The pick-up machine should be within about 150 feet of the mixing unit.The recycled material shall be spread in one continuous pass, withoutsegregation.

[0060] The above-described equipment (mixing unit, pick-up machine, andpaver) can be combined as a self-propelled paver with on-board mixingunit and emulsion tank, wherein millings are added directly to thehopper.

[0061] The cold recycled material cross slope shall be checked regularlyduring spreading using a level. The smoothness shall not vary more thanabout ¼ inches from the lower edge of a 10-foot straight edge placed onthe surface parallel and transversely to the centerline after rolling iscompleted.

[0062] Recycling shall be conducted in a manner that does not disturbthe underlying material in the existing roadway. The milling operationshall be conducted so that the amount of fines occurring along thevertical faces of the cut will not prevent bonding of the cold recycledmaterials. The pulverized bituminous material shall be processed byscreening and crushing to the required gradation. When a paving fabricis encountered during the CIR operation, necessary adjustments shall bemade in equipment or operations so that at least about ninety percent ofthe shredded fabric in the recycled material is no more than about 5square inches. Additionally, no fabric piece shall have any dimensionexceeding a length of about 4 inches. These changes may include, but notbe limited to, adjusting the milling rate and adding or removing screensin order to obtain a desired recycled material.

[0063] Another aspect of the present invention is on-site monitoring ofthe process. The nominal depth of milling shall be checked on bothoutside vertical faces of the cut about every ⅛ mile. The gradation ofthe RAP is also checked. If samples of the recycled asphalt pavementprior to emulsion addition are taken during operation of the equipment,they must be put into a sealed container so as not to allow any loss ofmoisture. Samples must be mixed with the field emulsion within 24 hoursand tested according to the mix design so as to meet the specificationsdefined, as required in Table 3. In addition, if samples of blendedmixture are tested, these samples must be compacted within 15 minutes ofsampling and then testing according to the mix design specifications.

[0064] Wet density of the newly spread CIR layer shall be determinedusing a nuclear moisture-density gauge. It is determined to establishthe roller pressure and patterns to achieve the required density.Preferably, using a backscatter method, the Standard Test Method forDensity of Bituminous Concrete in Place by Nuclear Methods (ASTM D2950)is followed for determining wet density. A rolling pattern will beestablished such that a maximum density is achieved with the rollersspecified, based on relative nuclear density readings. However, careshould be taken not to over-roll the mat based on visual observations ofcracking. A new rolling pattern shall be established if the materialbeing recycled changes. More than one roller pattern may be neededbecause of variance in the existing pavement, because of variations inaggregate, or because of variations in emulsion used.

[0065] Compacting of the recycled mix shall be completed using rollers.Preferably, the rollers have water and scraper systems for keeping thetires and rollers from sticking to the freshly applied CIR material.Rolling patterns shall be established to achieve a maximum densitydetermined by nuclear density testing. Rolling shall be continued untilno displacement is occurring or until the pneumatic roller(s) is (are)walking out of the mixture. Final rolling to eliminate pneumatic tiremarks and to achieve density shall be done by double drum steelroller(s). The selected rolling pattern shall be followed unless changesin the recycled mix or placement conditions occur and a new rollingpattern is established at that time. Rolling or roller patterns shallchange when major displacement and/or cracking of the recycled materialis occurring. Rollers shall start compacting typically within 15 minutesof placement of the CIR layer. Preferably, rolling shall start no morethan about 30 minutes behind the paver. Preferably, rolling shall becompleted no more than one hour after milling is completed. Whenpossible, rolling shall not be started or stopped on uncompactedmaterial but with rolling patterns established so that rolling begins orends on previously compacted material or the existing pavement.

[0066] After the completion of compaction of the recycled material, notraffic shall be permitted on the recycled material for at least abouttwo hours. This may be reduced if sufficient cure is established fortraffic that will not initiate raveling. After opening the roadway totraffic, the surface of the recycled pavement shall be maintained in acondition suitable for the safe movement of traffic. All loose particlesthat may develop on the pavement surface may be removed by powerbrooming.

[0067] The CIR material alone can support traffic prior to placement ofa wearing surface thereon. Before placing a wearing surface or treatmenton the CIR layer, the CIR layer shall be allowed to cure until itsmoisture is reduced to about 1.5% by weight or less. The wearing surfacemay be a cold, hot, or warm mix overlay, a sealcoat, a chip seal, a fogseal, or other surface treatment. Because the CIR surface can supporttraffic, the placement of a wearing surface can be delayed for severaldays if desired.

[0068] Preferably, the process of the present invention is performed ator above about 50° F. Preferably, no fog or rain is present. Preferably,there are no freezing temperatures within 48 hours after placement ofany portion of the project.

[0069] The cold in-place recycling process of the present invention canremove thermal and reflective cracks, re-establish crowns, maintainclearances and curb heights, improve poor aggregate gradations, improvepavement quality with additives such as polymers, be higher quality thanthe original pavement, re-use existing materials, minimize the need fornew materials, minimize lane closure time, and provide a new, smoother,black surface. The CIR method of the present invention improvesraveling, isolated rutting, consistency in emulsion content, extendedcuring time, compaction problems, disintegration under traffic, moisturesusceptibility, and crack resistance. It is more consistent, morepredictable, has improved performance, better coating, longerdurability, and higher film thickness than conventional CIR materials.

[0070] The CIR process of the present invention also creates more timefor application in days per year because the process can be conducted atlower temperatures than conventional processes and in hours per daybecause the CIR material is compacted quicker than conventionalprocesses. Some traffic can be supported by the new road within an hour,and large trucks can travel on the road within 2 hours of it being laid.When the CIR material created during the process of the presentinvention has reached the end of its life cycle, the recycled pavementcan be recycled itself.

EXAMPLE 1

[0071] A cold in-place recycling (CIR) project was done on US-191 inArizona, which is at an elevation of approximately 5610 feet, requiringabout 245,040 square meters of CIR material. The terrain of the road wasrelatively flat. Normal high and low temperatures and normalprecipitation for this area are shown in Table 6. TABLE 6 May June JulyAugust September High temp., ° F. 78 88 92 89 82 Low temp., ° F. 42 5159 58 49 Normal 0.53 0.27 1.31 1.37 0.93 precipitation, in.

[0072] The average daily traffic was 525 vehicles per day and 60 trucksper day. The annual cumulative 18 kip single axle equivalents (ESAL) was13,000. The 20-year ESAL was 317,000. The average pavement thickness wasapproximately 5.5 inches of hot mix asphalt. The pavement was over 20years old with several seal coats thereon.

[0073] The FHWA LTPPBind™ (Version 2.1) program recommended a binder towithstand 64° C. pavement temperatures for the surface mix (98%reliability). The 86% reliability value for the pavement surfacetemperature was 58° C.

[0074] Laboratory crushed CIR millings were obtained from this projectand sent to a laboratory for evaluation. Mix designs were performedusing the process of the present invention. Oven ignition was performedon the millings, and they were found to have 6.3% by weight asphalt.Parent rock consisted of rounded and crushed material. The gradation ofthe parent rock is shown in FIG. 1. This is a 0.45 power gradationgraph. The x-axis represents several sieve sizes. From right to left,they are as follows: 1 inch, ¾ inch, ½ inch, ⅜ inch, No.4, No.8, No.16,No.30, No. 50, No. 100, No. 200. The y-axis is the cumulative percentpassing through the particular sieve. The straight unlabeled line is themaximum density line, a reference line. The separation in this line isthe restricted zone.

[0075] Material above 1 inch in size was screened out before mixing. Themix design was performed with a Superpave™ gyratory compactor in a100-mm mold to 30 gyrations. Short-term strength tests were performedcomparing conventional CIRmaterial and the CIRmaterial obtained from theprocess of the present invention. Long-term cured specimens were testedfor strength and retained strength after water saturation.

[0076] Specimens were made with 2.5% by weight emulsion and were curedafter compaction at 30° C. and 50% humidity to simulate a worst-casescenario for field curing. After 4 hours and 24 hours, individualspecimens were tested for indirect tensile strength.

[0077] After testing, the internal coating of the specimens created bythe CIR process of the present invention was better than that ofconventional CIR specimens. A 19% increase in strength of the CIRmaterial of the process of the present invention over conventional CIRmaterial was observed in the 4-hour specimens, and a 38% increase instrength of the CIR material of the method of the present invention wasobserved in the 24-hour specimens. Specimens made by the CIR process ofthe present invention had a greater increase in strength from 4 to 24hours (49% vs. 32%).

[0078] Specimens were made with two different emulsion contents for bothconventional CIR and the CIR material of the present invention and werecured after compaction to less than one percent moisture. After curing,half the specimens were tested dry and half the specimens were vacuumsaturated with water and then soaked for 24 hours. The saturated datawas for an indication of durability (long-term strength). All specimenswere tested at 40° C. See Table 7 and FIG. 2. TABLE 7 Marshall stabilityand retained stability Emulsion content, % Retained Percent by weightAir Voids, % Saturation, % Stability, lb stability, lb Retained Conv.CIR 1.5 13.5 77 1858 690 37 material 2.5 12.4 74 2044 749 37 CIR 2.512.4 75 1727 1037 60 material 3.5 11.0 77 1773 949 54 obtained by theprocess of the present invention

[0079] Cores were obtained and crushed, except cores 5 and 6. Ovenignition was performed on the millings, and the asphalt content of thecombined crushed cores was 6.2% by weight. The asphalt content of cores5 and 6 was 6.9% by weight.

[0080] Lab design called for 2.5% by weight emulsion content. Theemulsion varied from 1.9% to 3.0% by weight. An emulsion content of 1.9%by weight was used on a section of pavement with high asphalt content(measured from the cores during design). This content still appeared tobe low. The material in the field crushed finer than the originaldesign. The emulsion content on the last 1,600 feet was increased to 3%by weight. There were no problems with this emulsion content.

[0081] The milling depth was three inches. The millings were blendedwith conventional CIR material in most of the project. The last 6.5miles used the CIR material created from the process of the presentinvention. Cores were taken and a mix design was performed. Core data isshown in Table 8. Stations describing project events are shown in Table9. After the CIR layer was placed, the entire project was overlaid withtwo inches of hot mix asphalt.

[0082] Nuclear density testing results are shown in Table 10. Nucleardensity testing results on mixes with moisture typically only showtrends and not true density values or true moisture contents. The rollerpattern was 3 passes of a steel wheel followed by 13 passes of pneumatictire rollers.

[0083] There was some raveling on the last sections completed on thefirst day and on the n completed using 1.9% by weight emulsion content.Raveling was minor and was a result of pickup and, in one section, lowemulsion content. Roller pickup was due to the scrapers and system onthe rollers not working.

[0084] Trucks were on the mat at most three hours after milling with nosigns of rutting. TABLE 8 Existing pavement thickness and core data CoreLocation Depth number (station) (mm) Comments 1 743 + 520 100 Mostlygravel mix with double seal 2 744 + 090 87 ″ 3 744 + 510 87 ″ 4 745 +134 100 ″ 5 745 + 410 130 Contained crushed layer with single seal 6745 + 740 125 ″ 7 746 + 400 113 Mostly gravel mix with double seal 8746 + 670 100 ″ 9 746 + 970 113 ″ 10 747 + 210 125 ″ 11 747 + 810 119Contained crushed layer with single seal 12 748 + 410 100 ″ 13 748 + 800106 Mostly gravel mix with double seal 14 749 + 760 100 ″ 15 749 + 970100 ″ 16 751 + 320 92 ″

[0085] TABLE 9 Project history and emulsion contents Emulsion LocationComments content STA 754 + 080 (˜MM 468.5) Where The CIR process of thepresent invention 2.5% by weight started on first day STA 753 + 630 Areaof pneumatic tire pickup - some raveling. 2.5% by weight Water on tiresfixed. STA 752 + 400 Emulsion content lowered 2.15% by weight STA 750 +360 CIR train down 1.5 hours - pump plugged STA 749 + 806 (˜MM 466)Slight raveled area going to STA 748 + 680 ˜STA 749 + 760 2.3% by weight˜STA 749 + 310 2.45% by weight STA 748 + 680 Station at end of first day2.3% by weight STA 748 + 680 Start of second day 2.6% by weight STA746 + 340 (near MM 464) High asphalt content in pavement and existing1.9% by weight pavement flushed; minor raveling STA 745 + 620 Mixappeared very rich - slowed paver down - 1.9% by weight much hand workSTA 744 + 660 2.2% by weight STA 743 + 940 2.7% by weight STA 743 + 9103.0% by weight STA 743 + 402 (MM 462) End of project 3.0% by weight

[0086] TABLE 10 Nuclear testing results Location Density, pcf Moisture,% Date (station) Design = 127.1 by weight construct Comments 753 + 630122.2 4.7 5-24 Raveled area/under- rolled 753 + 600 122.9 5.0 5-24Raveled area/under- rolled 753 + 300 116.2 4.8 5-24 Roller problems752 + 700 125.3 5.2 5-24 752 + 400 117.5 4.3 5-24 752 + 100 121.0 3.55-24 751 + 800 119.1 3.5 5-24 751 + 500 119.5 4.2 5-24 751 + 200 122.04.0 5-24 750 + 900 126.1 4.6 5-24 750 + 600 122.4 4.0 5-24 750 + 300120.3 4.0 5-24 750 + 000 119.5 4.0 5-24 749 + 700 123.0 4.6 5-24 749 +400 120.5 4.5 5-24 749 + 100 120.3 9.6 5-24 748 + 800 121.3 9.8 5-24748 + 560 119.4 4.7 5-25 748 + 260 120.9 3.8 5-25 747 + 960 118.6 4.45-25 747 + 540 121.1 4.1 5-25 747 + 180 122.3 4.1 5-25 746 + 940 122.94.0 5-25 746 + 610 119.6 4.4 5-25 746 + 220 119.7 4.0 5-25 745 + 830122.7 3.4 5-25 745 + 560 125.1 4.3 5-25 745 + 230 120.1 4.8 5-25 745 +830 122.7 3.4 5-25 745 + 560 125.1 4.3 5-25 745 + 230 120.1 4.8 5-25745 + 020 118.9 4.1 5-25 744 + 720 120.5 3.4 5-25 744 + 480 119.0 3.45-25 744 + 120 119.3 4.2 5-25 743 + 730 118.7 3.7 5-25

[0087] After the project was completed, field cores were taken from thecomparative project on US 191 in Arizona. These cores were tested underwater in an Asphalt Pavement Analyzer (APA), which is a wheeltrackingdevice. FIG. 3 shows the core of the CIR invented process rutted lessthan the conventional CIR, even though the core of the CIR inventedprocess had a higher emulsion content. This behavior was also documentedin the field. The conventional sections exhibited isolated ruttingshortly after application, and the sections with the CIR material of thepresent invention did not.

EXAMPLE 2

[0088] A cold in-place recycling (CIR) design was completed for US-281in South Dakota. The project was located at an elevation ofapproximately 1637 feet. Normal high and low temperatures and normalprecipitation for the area are shown in Table 11. TABLE 11 May June JulyAugust September High temp., ° F. 71 81 88 86 75 Low temp., ° F. 47 5763 61 51 Normal 3.6 3.4 2.8 2.3 1.9 precipitation, in.

[0089] The FHWA LTPPBind™ (Version 2.1) program recommended a binder towithstand 64° C. (almost 58° C.) pavement temperatures for a surface mix(at 98% reliability). The low temperature grade was −34° C. (almost −28°C.).

[0090] CIR millings were obtained at the beginning of this project andevaluated in a laboratory. Mix designs were performed using the CIRmethod of the present invention. Oven ignition was performed on themillings, and they were found to have 8.0% by weight asphalt. The parentrock consisted of 42% by weight 2-crushed faces, 18% by weight 1-crushedface, and 40% by weight uncrushed material. The gradation of the parentrock is shown in FIG. 4.

[0091] Material above 1 inch in size was screened out before mixing. Amix design was performed with a Superpave™ gyratory compactor in a100-mm mold to 30 gyrations. Short-term strength tests were performedcomparing conventional CIR material and the CIR material made from themethod of the present invention. Long-term cured specimens were testedfor strength and retained strength after water saturation.

[0092] Specimens were made with 1.5% and 3.0% by weight emulsion. Theywere cured after compaction at 30° C. and 50% humidity to simulate aworst-case scenario for field curing. After 4 hours, specimens weretested for indirect tensile strength. There was a 30% increase in theearly strength of the CIR material of the process of the presentinvention over conventional CIR.

[0093] A raveling test was performed on the materials at the anticipatedemulsion content from the mix design. Specimens were compacted to theapproximate density achieved during the design. FIG. 5 shows the resultsof the raveling test. This data indicates that the CIR material obtainedfrom the method of the present invention is much less likely to ravelunder traffic than the conventional CIR material.

[0094] Specimens were made with two different emulsion contents for bothconventional CIR and the CIR material of the process of the presentinvention and were cured after compaction to less than 0.5% moisture.After curing, half the specimens were tested dry and half the specimenswere vacuum saturated with water and then soaked for 24 hours. Thesaturated data was for an indication of long-term durability (long-termstrength). All specimens were tested at 40° C. TABLE 12 Marshallstability and retained stability Emulsion content, % Retained Percent byweight Air Voids, % Saturation, Stability, lb stability, lb RetainedConv. 1.5 11.5 62 1674 958 57 CIR 2.5 9.8 69 1276 841 66 material CIR2.5 10.2 67 1563 1227 78 material 3.5 9.2 61 1490 946 64 of the presentinvention

[0095] Results from both CIR materials were good. The CIR material ofthe process of the present invention overall had a better percentretained stability. It also had slightly better stability values. Mixesmade using the CIR process of the present invention had slightly bettercoating than conventional CIR material. The design was completed but theproject was not done using the designed mix developed from the processof the present invention due to time constraints.

EXAMPLE 3

[0096] A cold in-place recycling (CIR) project was done in Blue EarthCounty, Minn., where the elevation was approximately 836 feet. Normalhigh and low temperatures and normal precipitation are shown in Table13. Cores were taken and crushed in the laboratory in order to perform amix design. TABLE 13 May June July August September High temp., ° F. 7181 85 82 73 Low temp., ° F. 47 56 61 58 48 Normal 3.3 3.8 4.0 3.9 3.1precipitation, in.

[0097] The FHWA LTPPBind™ (Version 2.1) program recommended a binder forthe surface of Performance Grade (PG) 58-34 (at 98% reliability) and abinder of grade PG 58-28 at 92% reliability. A grade PG 58-40 binder wasused in the Superpave™ surface mix.

[0098] Cores were crushed, and different gradations were produced. Mixdesigns were performed using the process of the present invention withthe different gradations of millings. Oven ignition was performed on themillings, and they were found to be 6.5% by weight asphalt. Thegradation of the RAP millings is shown in FIG. 6.

[0099] Material above 1 inch in size was screened out before mixing. Themix design was performed with a Superpave™ gyratory compactor in a100-mm mold to 30 gyrations. Cured specimens were tested for strengthand retained strength after water saturation. A comparison was made toconventional CIR material with the medium gradation RAP. All specimenswere tested at 40° C. See Table 14 for data.

[0100] A raveling test was performed using the medium gradation RAPcomparing conventional CIR to CIR material made using the process of thepresent invention. An emulsion content of 1.5% by weight was used forthe conventional CIR material and 3.0% by weight for the CIR process ofthe present invention. Specimens were compacted to near the same densityachieved during design and allowed to cure at ambient laboratoryconditions before testing. After 15 minutes of testing, the specimensmade from the process of the present invention had 1.6% by weight loss.After 2.5 minutes of testing, the specimen made with conventional CIRmaterial had 25.7% by weight loss. TABLE 14 Marshall stability andretained stability Emulsion content, % Retained Percent by weight AirVoids, % Saturation, % Stability, lb stability, lb Retained Conv. CIR1.3 14.3 65 2093 876 42 Medium 2.0 13.2 63 2112 1060 50 gradation CIR2.0 11.9 76 1827 1428 78 material of 2.7 10.6 74 1824 1680 92 thepresent 3.4 9.1 80 1635 1361 83 invention Medium gradation CIR 2.0 13.472 2174 1439 66 material of 2.7 12.4 72 2025 1445 71 the present 3.411.6 69 1841 1484 81 invention Fine gradation

[0101] Unconditioned stability values for conventional CIR specimenswere higher than the CIR specimens of the process of the presentinvention. Although saturation levels were higher for the CIR specimensof the process of the present invention, they had better retainedstability values and retained percent values.

[0102] The fine and coarse gradations indicated no problems inshort-term or long-term performance. The recommended starting emulsioncontents were Medium gradation: 2.9±0.25%, Fine gradation: 3.2±0.25%,and Coarse gradation: 3.0±0.25%. Tolerances of±0.25% were allowed basedon coating and other visual factors observed in the field.

[0103] The following was the equipment used with the conventional train:milling machine approximately 12.5 feet wide; screening, crushing, andpugmill including shaker; 6,000 gallon tanker; pick-up device; paverwith tracks; and screed (12 feet) with strike-off plate in front ofextensions.

[0104] Gradation was checked in the field on the first, second, andfourth days of production with the conventional train/paver process andthe CIR material of the invented process. In order to obtain a quickerresult, the material was not fully dried but was aerated before testing.The results are shown in Table 15. TABLE 15 Gradation results from BlueEarth County samples Day 1 Day 21 Day 2 Day 4 Day 4 Fine Mix Med. Coarsea.m. 10:30 3:00 7:45 11:30 Design Mix Mix On-Site On-site On-site In labIn lab Design Design 1.5 in. 100 100 100 100 100 1 in. 100 100 100 100100 100 100 100 3/4 in. 92 97 98 96 97 99 98 93 ½ in. 70 84 88 79 78 9479 68 3/8 in. 56 75 78 67 64 90 64 55 No.4 31 52 52 42 37 78 43 37 No.819 35 34 25 20 51 30 26 No. 30 5.1 10.7 9.1 8.0 5.6 20 10.2 8.6 H₂O, %by — — — 2.8 1.7 weight Approx. Milled Milled Milled Milled Milledgraduation once. twice. twice. once. once. Coarse Med.- Med.- MediumMed.- fine fine coarse

[0105] The three mix designs were chosen that bracketed the gradation inthe field. The “milled twice” comment was for millings that were infront of the milling machine when parts of the road were corrected(geometrics, etc.), and it was not known if these millings were similarin nature to the rest of the road.

[0106] The average emulsion content was estimated to be 3.25% by weight.This was estimated from approximately 4,738 tons of RAP (approximateafter moisture correction) and 154 tons of CIR material of the inventedprocess. On the cold in-place recycled surface of the present invention,four surface treatments were applied on various sections of the road, atwo inch Superpave™ overlay (one mile), fog seal (0.25 mile), chip seal(0.25 mile), and double chip seal (0.25 mile).

[0107] After the project was complete, a new testing device was alsoused on the project in Blue Earth County, Minn. Pavement strength wasdetermined using a Humbolt Stiffness Gauge. This hand portableinstrument imparts a very small displacement to the newly recycledpavement at 25 steady state frequencies between 100 and 196 Hz.Stiffness was determined at each frequency, and the average wasdisplayed. At the low frequencies used, the impedance at the surface wasstiffness controlled and proportional to the shear modulus of therecycled material. Stiffness was measured with a Humboldt stiffnessgauge on the CIR material of the invented process and the conventionalCIR. The stiffness values of CIR material of the invented process afterone day were higher than the values of the conventional CIR materialafter one week. See FIG. 7.

EXAMPLE 4

[0108] A cold in-place recycling (CIR) project was done in WhitmanCounty, Wash. Cores were taken and crushed in the laboratory in order toperform mix designs. This project demonstrated differences betweenconventional CIR material and the CIR material of the process of thepresent invention. The elevation was approximately 2545 feet. Normalhigh and low temperatures and normal precipitation are shown in Table16. TABLE 16 May June July August September High temp., ° F. 64 72 81 8272 Low temp., ° F. 41 47 50 50 44 Normal precipitation, 1.6 1.4 0.7 0.91.0 in.

[0109] The FHWA LTPPBind™ (Version 2.1) program recommended a binder forthe surface of grade PG 58-28 (at 98% reliability). A grade PG 64-28binder was used in the surface mix.

[0110] Cores were obtained in the area to be recycled and sent to alaboratory for evaluation. Cores were crushed, and different gradationswere produced to anticipate gradations of the millings during theproject. A fine millings gradation was not evaluated due to theexcessive crushing in the lab that was necessary to obtain the mediumand coarse gradations. The excessive crushing indicated that a finegradation was probably not obtainable using typical cold in-placerecycling milling equipment. Mix designs were performed with the CIRmaterial created by the process of the present invention using thedifferent gradations of millings. Oven ignition was performed on themillings, and they were found to have 6.7% by weight asphalt. All rockexamined after oven ignition was observed to be angular. The gradationof the RAP millings is shown in FIG. 8.

[0111] There was debonding between many of the layers, which could showup as fatigue cracking on the pavement surface. No visual stripping wasobserved. A stripping test, AASHTO T283, was performed on four cores todetermine if stripping was present or if the mixes had the potential tostrip. After saturating the specimen voids with water to 75%, freezingfor 30 hours, submerging the specimens for 23 hours at 60° C., andtesting at 25° C., the indirect tensile strength ratio was 63%. ASuperpave™ mix design requires 70 or 80% retained strength on freshlyprepared hot mix specimens. No visual stripping was observed in theconditioned specimens. This testing indicated that stripping wascurrently not occurring.

[0112] Material above 1 inch in size was screened out before mixing. Adesign was performed with a Superpave™ gyratory compactor in a 100-mmmold to 30 gyrations. Long-term cured specimens were tested for strengthand retained strength after water saturation. A comparison was made toconventional CIR material with lime using the medium gradation. The CIRmaterial of the present invention (2.7% by weight emulsion) with limewas also compared to the CIR material of the present invention with nolime. Lime was added as a slurry, and the lime solids content was 1.5%by weight.

[0113] A raveling test was performed using the medium gradationcomparing conventional CIR (with lime) to the CIR material created bythe process of the present invention. Specimens were compacted to aboutthe same density achieved during design and allowed to cure for fourhours at ambient laboratory conditions before testing. The loss ofconventional CIR material was 16% by weight after 4 minutes. The loss ofthe CIR material created by the process of the present invention was1.5% by weight after 15 minutes.

[0114] Specimens were made with different emulsion contents for eachgradation type and were cured after compaction to less than 0.5%moisture. The medium gradation was used for conventional and inventedCIR materials. Coarse gradation specimens with and without lime werealso tested.

[0115] After curing, a moisture susceptibility vacuum saturation testusing Marshall stability was performed on specimens that were vacuumsaturated with water and then soaked for 24 hours. The saturated datawas an indication of long-term durability. Hveem stability at 40° C. wasmeasured for dry strength. All specimens were tested at 40° C. See Table17 for data. TABLE 17 Emulsion Dry Retained content, % Hveem Marshallstability, Percent by weight Air Voids, % Saturation, % StabilityStability, lb lb Retained Conv. CIR/lime 1.0 17.1 67 13.0 2016 1825 91Medium 1.7 16.5 68 12.5 2570 1945 76 Gradation 2.4 15.1 68 10.7 24732103 85 CIR material 2.0 16.5 62 11.9 2507 1909 76 of the presentinvention Medium 2.7 14.9 62 11.5 2090 1933 92 Gradation 3.4 14.0 6511.0 1691 2156 128 CIR material of 2.0 14.2 65 12.5 2167 1783 82 thepresent invention Coarse 2.7 13.9 68 11.5 2607 1811 69 gradation 3.413.4 70 11.1 2237 1588 71 CIR material of 2.7 13.5 61 8.8 2193 2021 92the present invention/lime Coarse Gradation

[0116] The coating of the CIR material of the process of the presentinvention was superior to the coating of the conventional CIR with limespecimens. The specimens of the CIR process of the present invention hadslightly better retained strength values after moisture conditioning.

[0117] The coarse gradation strength and volumetric measurementsindicated no significant differences from the medium gradation samples.

[0118] The recommended starting emulsion contents for the CIR materialof the process of the present invention were medium gradation of 3.0 to3.4% and coarse gradation of 3.0 to 3.4%. These numbers depend on thegradation produced by milling, crushing, and screening. Tolerances of0.25% were allowed based on coating and other visual factors observed inthe field.

[0119] Long-term strength values, as measured by Marshall stability andHveem stability on specimens cured to less than 0.5% moisture, werecomparable between conventional CIR and CIR specimens made by theprocess of the present invention. Retained stability values after watersaturation were slightly higher for the CIR specimens of the process ofthe present invention. The improved coating in the CIR specimens of theprocess of the present invention was a factor in the higher retainedstability values, which are an indicator of long-term durability.

[0120] The gradations from the RAP in Washington are listed in Table 18.These gradations fit into the range of those for the mixture testingdone in the project design.

[0121] Recycled mixes were taken from the field project on WashingtonState US 270. These mixes were compacted in the laboratory and testedfor resilient modulus. FIG. 9 shows a much higher modulus for the CIRmaterial of the process of the present invention than for theconventional mixture.

[0122] Resilient Modulus specimens were made from the project millingsand emulsion samples in the laboratory on the Superpave™ gyratorycompactor. The Resilient Modulus testing was completed by thelaboratory, and the summary of the results can be seen in Table 19. Thevoids were also tabulated for these specimens in Table 19 and are closeto those tested for the original mix design. The more detailed testresults for the Resilient Modulus are shown in Tables 20 and 21 for theCIR material of the process of the present invention and conventionalCIR, respectively.

[0123] Indirect tensile specimens for thermal cracking were made fromthe project millings and emulsion samples in the laboratory. FIG. 10shows the IDT graphical results of this testing for the CIR materialwith 3% by weight emulsion made by the process of the present invention.The conventional CIR specimens were not consistent enough to analyze.The results predicted an initiation of thermal cracking at −26° C. forthe CIR material made by the present invention. TABLE 18 Field GradationResults Agg type 11:30 a.m. Percent used Milling no lime Millings withlime 1¼ IN* 98.5 98.6 1 IN 94.9 96.9 ¾ IN 82.5 83.8 ½ IN 72.3 71.5 ⅜ IN61.8 58.5 # 4 33.0 32.8 # 8 18.4 18.1 # 10 18.4 18.1 # 16 10.4 10.4 # 306.9 6.9 # 40 6.9 6.9 # 50 4.9 4.8 # 80 4.9 4.8 # 100 3.5 3.4 # 200 2.62.5 % MOISTURE 2.64 2.49

[0124] TABLE 19 Resilient Modulus Summary and Air Void Data The CIRprocess of Emulsion the present invention CMS/Lime Resilient Modulus375816 295480 Results, M_(R) @ 25° C.

[0125] The samples were cured at 60° C. for 48 hours. The testing wascompleted within one week and the samples were at ambient conditionsduring that time. TABLE 20 Resilient Modulus Data—3% by weight The CIRprocess of the present invention Emulsion (no lime slurry)

[0126] TABLE 21 Resilient Modulus Data—2% Conventional CIR Material(lime slurry)

A COMPARISON OF EXAMPLES 1-4

[0127] Materials from four different projects were tested with bothconventional CIR and the CIR specimens created by the designs of thepresent invention. Table 22 shows Marshall stabilities that are roughlyequivalent for both the invented recycled mixes and the conventionalsystems used on the field projects. After soaking, the CIR specimens ofthe process of the present invention have higher retained stabilitiesthan the conventional mixes. TABLE 22 Marshall Stability Data (40° C.)Arizona Minnesota Washington US 191 Blue Earth County South Dakota SR270 CIR of CIR of CIR of The CIR process process of process of processof the the the of the present present present present Type of Emulsioninv. Conventional inv. Conventional inv. Conventional inv. ConventionalStability (dry), lbs 1750 1860 1730 2100 1530 1470 1890 2520 Stability(soaked) lbs. 990 690 1520 970 1090 900 2040 2250

[0128] From the foregoing, it will be seen that this invention is onewell adapted to attain all the ends and objects herein above set forthtogether with other advantages which are obvious and inherent to thestructure. It will be understood that certain features andsubcombinations are of utility and may be employed without reference toother features and subcombinations. This is contemplated by and iswithin the scope of the claims. Since many possible embodiments may bemade of the invention without departing from the scope thereof, it is tobe understood that all matter herein set forth or shown in theaccompanying figures is to be interpreted as illustrative and not in alimiting sense.

We claim:
 1. A method of reconstructing a paved road, comprising: taking cores of said road; analyzing said cores; crushing said cores to form recycled asphalt pavement particles; selecting a substantially solvent-free emulsion based on climate history and application temperature; mixing said emulsion and said reclaimed asphalt pavement particles to form an asphalt emulsion mixture; and testing said asphalt emulsion mixture for performance using a raveling test, a thermal cracking test, a moisture susceptibility vacuum saturation test, and a dry Marshall stability test.
 2. The method of claim 1, further comprising: milling pavement off said road to form reclaimed asphalt pavement particles and leaving at least about an inch of said pavement on said road; mixing said reclaimed asphalt pavement particles with said emulsion to form a cold in-place recycling layer; and applying said cold in-place recycling layer to said road.
 3. The method of claim 2, further comprising: compressing said CIR layer with a roller, wherein said roller may be placed on said CIR layer up to about an hour after said layer is applied.
 4. The method claim 1, further comprising: evaluating said road before taking cores of said road.
 5. The method of claim 4, wherein said evaluation includes inspecting said road to determine if said road is thick enough to leave at least about an inch base of pavement after milling, determining if said road has a structurally sound base, and determining if said road has good drainage.
 6. The method of claim 3, further comprising: applying a wearing surface selected from the group consisting of a cold, hot, or warm mix overlay, a sealcoat, a chip seal, a fog seal, or other surface treatment.
 7. The method of claim 1, wherein said cores are representative of variations in the road.
 8. The method of claim 7, wherein at least two asphalt emulsion mixes are formulated for at least two for different parts of the road having different compositions.
 9. The method of claim 1, wherein said emulsion is comprised of emulsifier, asphalt solids, and water.
 10. The method of claim 1, wherein said mixture is further comprised of lime, rock, polymer, elastomers, plastomers, other adhesion agents, and petroleum fractions or combinations thereof.
 11. The method of claim 9, wherein said emulsion is solventless.
 12. The method of claim 9, wherein said emulsifier is cationic.
 13. The method of claim 2, wherein said CIR layer is able to support traffic.
 14. The method of claim 3, wherein said roller rolls no more than about 30 minutes behind the paver.
 15. The method of claim 2, wherein said method can be performed at temperatures of at least about 50° F.
 16. The method claim 1, wherein said asphalt emulsion mixture ravels no more than about 2% by weight after curing for at least about 4 hours, a critical cracking temperature that is at least as low as the possible coldest temperature of said road with 98% reliability, and said asphalt emulsion mixture has a retained strength of at least about 70%.
 17. The method of claim 2, wherein about 100% of said reclaimed asphalt pavement particles are able to pass through a 1.25 inch sieve.
 18. The product of the process of claim
 2. 19. The product of the process of claim
 3. 20. The product of the process of claim
 6. 21. A CIR layer of a road that is constructed using a mix design, comprising the mixture of: an asphalt emulsion and reclaimed asphalt pavement particles, wherein said CIR layer is designed from a mix design that ravels no more than about 2% by weight after curing for at least about 4 hours, a critical cracking temperature that is at least as low as the possible coldest temperature of said CIR with 98% reliability, and that has a retained strength of at least about 70%.
 22. The layer of claim 21, wherein about 100% of said reclaimed asphalt pavement particles are able to pass through a 1.25 inch sieve.
 23. A method of reconstructing a paved road, comprising: evaluating said road by inspecting said road to determine if said road is thick enough to leave at least about an inch base of pavement after milling, determining if said road has a structurally sound base, and determining if said road has good drainage. taking cores of said road; analyzing said cores; crushing said cores to form recycled asphalt pavement particles; selecting a substantially solvent-free emulsion based on climate history and application temperature; mixing said emulsion and said reclaimed asphalt pavement particles to form an asphalt emulsion mixture; and testing said asphalt emulsion mixture for performance using a raveling test, a thermal cracking test, a moisture susceptibility vacuum saturation test, and a dry Marshall stability test; milling pavement off said road to form reclaimed asphalt pavement particles and leaving at least about an inch of said pavement on said road; mixing said reclaimed asphalt pavement particles with said emulsion to form a cold in-place recycling layer; applying said cold in-place recycling layer to said road; compressing said CIR layer with a roller, wherein said roller may compress said CIR layer up to about an hour after said layer is applied; and applying a wearing surface selected from the group consisting of a cold, hot, or warm mix overlay, a sealcoat, a chip seal, a fog seal, or other surface treatment.
 24. The product of the process of claim
 23. 